Centrifugal machine for screening pulp and paper-stock.



No. 772,373. PATENTED OCT. 18,1904. T. QV ILLER & H. STUB. I

GENTRIFUGAL MACHINE FOR SCREENING PULP AND PAPER STOCK.

APPLICATION FILED DEC. 30, 1903.

NO MODEL.

Fig.1

UNITED STATES Patented October 18, 1904.

PATENT OEEIcE.

THEODOR QVILLER, OF ESSVIK, SWEDEN, AND HANS STUB; OF OHRISTIANIA, NORWAY.

CENTRIFUGAL MACHINE FOR SCREENING PULP AND PAPER-STOCK.

SPECIFICATION forming part of Letters Patent No. 772,373, dated October 18, 1904.

i Application filed December 30, 1903. Serial No. 187,188. (No model.)

To (ZZZ whom it may concern:

Be it known that we, THEODOR QVILLER, residing at Essvik, near Sundsvall, Sweden, and HANS STUB, residing at Christiania, Norway, subjects of the King of Sweden and Norway, have invented certain new and useful Improvements in Centrifugal Machines for Screening Pulp and Paper-Stock; and we do hereby de-v clare the following to be a full, clear, and eX- act description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to figures of reference marked thereon, which form a part of this specification.

Our invention relates to centrifugal machines for screening pulp and paper-stock, and more especially to that type of such machines in which the stock is thrown against a circular pulp-screen by means of a Wheel provided with wings mounted inside the screen and rotating with a high speed, whereby the fine stock will by the centrifugal action be pressed through the screen and gathered on the other side, while the coarse fibers or slivers are withheld by the screen and conveyed away for further treatment.

The object of our invention is to improve the said type of centrifugal screening -machines, first, so that their efliciency shall be increased; secondly, so that as little as possible of the fine stock shall be carried away with the coarse fibers, and so that the coarse fibers shall be obtained in as dry state as possible.

With these ends in view our invention consists in means for spreading the stock in a thin and uniform layer on the wings, whereby it will hit the screenin broad streams of uniform thickness.

It also consists in means whereby the thickness of these streams may be easily regulated at will, according to the nature of the stock and other circumstances.

It further consists in means for providing a certain vibration of the air surrounding the screen for the purpose of facilitating the pas sage through the screen of the fine particles and the droppingdown of the coarse particles. In the drawings, Figure 1 shows a vertical axial section through one form of our improved centrifugal pulp-screen. Fig. 2 is a horizontal section, and Fig. 3 a detail, being a developed cylindrical section through part of the distributing-channels. Fig. 4c is a vertical axial section through another embodiment of our invention.

Referring more particularly to Figs. 1, 2, and 3, 1 represents the circular screen, which is mounted in a suitable way between the basecasting 6 and the top casting 5 of the machine. 3 is the outer shell of the machine, being also fixed in. suitable way between the said two castings. 2 represents the wings of the centrifugal wheel 7, which is keyed or otherwise secured to the axle 8. The upper hub of the wheel is united with the wheel 7 itself by a conical part 10, between which and the top casting there is in this manner formed a passage for the stock, which enters the machine through a pipe connected to the opening 4 and passes down over the cone 10 in the form of a conical disk-shaped stream, the thickness of which may be regulated by way of a ringgate 11, which may be moved vertically by means of rods, as indicated, or in any other suitable way. From the foot of the cone 10 channels or tubes 9 are led in an inclined position, as clearly shown in Fig. 3. There are a number of such channels in each space between the wings close to the outer side of the wheel -cylinder 7, and they have their lower openings in a short distance from a wing. The stock will therefore be distributed over the wing in its whole height. These channels may be tubes, as shown, or may be cast in the wheel. They need not be closed on the inward side, because the centrifugal force will press the stock outwardly. 12 represents openings in the top of the machine through which a clearing out of the channels may be eifected by means of a water-jet during the working of the machine and by means of stakes when the machine is at rest. fine stock is gathered in a circular trough 13, from which it is carried away througha chute 15. The coarse fibers are gathered in the trough 14 and are conveyed from here through the chute 16.

We find it advantageous to allow air to en- The pulp and paper-stock, the combination with ter the machine and to do this in such way that a vibratory air-current presses on the screen 1. This may be effected by providing in a flange 17, which projects from the bottom casting 6 of the machine to close underneath the centrifugal wheel, openings 18 and providing similar openings 20 in a flange 19, projecting downwardly from the wheel. When the wheel revolves, these openings will intermittently correspond with each other and be covered by the flanges, whereby the vibrations in the air will be created. The wings 2 will by their suction cause air to enter through the said openings, and, if necessary, special wings for this purpose may be arranged on the lower side of the wheel. This vibratory air-stream will act to loosen the fibers accumulating in the perforations of the screen, and also according to our experience involves a less percentage of water in the coarse stock gathered in the trough 14.

v In the modification shown in Fig. 4 the wings 2 are carried by only one hub 21, and the distributing-tubes 9 do not therefore rotate with the wheel, but are stationary, the cone 10 being mounted on the top casting of the machine. In this case the lower openings of the tubes have to be directed outwardly, as shown. The machine may in other respects be like the first-described modification.

From the above it will be understood that by our machine we are able to distribute the stock over the whole height of the screen in a uniform layer, as by regulating the valve 11 the amount of stock .passing to each channel will be exactly regulated. In other known apparatus a regulating of the flow of stock into the centrifuge will only or chiefly have the result that more or less of the screen-surface will be utilized, and a regulation of the thickness of the layer is therefore hardly possible by these apparatus.

We claim- 1. In a centrifugal machine for screening pulp and paper-stock, the combination with a stationary screen and a rotary element having wings for throwing stock onto the screen, of an axial receiver for said stock, and means on the rotary element to distribute the stock to different levels of said wings.

2. In a centrifugal machine for screening pulp and paper-stock, the combination with astationary screen and a rotary element having wings for throwing stock onto the screen, of a receiver mounted axially of the Wings, and a plurality of channels on the rotary element adapted to distribute the stock from the receiver to different levels of the wings.

3. In a centrifugal machine for screening a stationary screen and a rotary element having wings for throwing stock onto the screen, of a receiver mounted axially of the wings, and a plurality of chambers of varying length adapted to convey the stock from the receiver to different levels of the wings.

4. In a centrifugal machine for screening pulp and paper-stock, the combination with a stationary screen and a rotary element having wings for throwing stock onto the screen, of an axial receiver for said stock, means on the rotary element to distribute the stock to different levels of the wings, and means cooperating with the receiver to vary the flow of stock to the distributing means.

5. In a centrifugal machine for screening pulp and paper-stock, the combination with a stationary screen and a rotary element having wings for throwing stock onto the screen, of a receiver mounted on and rotatable with the rotary element, a plurality of tubes on the latter leading from the receiver to different levels of the wings,'and an adjustable regulator cooperating with the receiver.

6. In a centrifugal machine for screening pulp and paper-stock, the combination with a stationary screen, of a rotary element, means for feeding stock to the upper and central part of said element, means for dispersing the stock radially and uniformly on said element, means for regulating the thickness of the stock, means for dividing up the stock into a plurality of streams, wings for throwing the stock onto the screen, and means for conveying the divided streams in a downward direction to dif ferent levels of said wings.

7. In a centrifugal machine for screening pulp and paper-stock, the combination with a stationary screen, of a rotary element, a tapering receiver formed on the central top portion of said element, means for feeding stock onto the receiver, a gate movable to and from said receiving member, a plurality of channels leading from the receiver and terminating at different levels, and wings adapted to throw the stock onto the screen.

8. A centrifugal machine for screening pulp and paperstock comprising a stationary screen, a base supporting said screen having a plurality of air-ports, a rotary beater comprising a central drum"mounted above said base and having ports thereon adapted to register with the aforesaid ports, means for feeding stock onto said drum, wings on said drum, and means surrounding the drum for conveying stock from the drum to different levels of the wings.

9. A centrifugal machine for screening pulp and paper-stock comprising a screen, a supporting-base therefor having a plurality of air-ports, a rotary beater comprising a central drum mounted above said base concentric to the screen and having ports adapted to register with the aforesaid ports, a tapering top on said drum for the reception of the stock, wings on the drum, and means between the wings for conveying stock from the drum-top to different levels of the wings.

10. A centrifugal machine for screening pulp and paper-stock comprising a stationary screen, a supporting-base therefor having a plurality of air-ports, a shaft journaled in the shell, a stationary screen concentrically mounted therein, a supporting-base therefor having a central perforated portion concentric to the screen, a shaft journaled in the base, a drum fixed on the shaft surrounding the central base portion and provided with ports adapted to register with said perforations, a tapering top on said drum, means for feeding stock onto said top, radial Wings on the drum, and a plurality of downwardly-extending channels on the periphery of the drum between the wings.

12. A centrifugal machine for screening pulp and paper-stock comprising an outer shell, a stationary screen concentrically mounted therein,a supporting-basethere for having a central perforated portion projecting centrally within the screen, a vertical shaft journaled in the base, a drum fixed on the shaft surrounding the central base portion and pro vided with ports adapted to register with said perforations, a tapering receiver on the drum, means above the receiver for feeding stock thereon, radial wings on the drum, a plurality of channels between the wings extending from the receiver to different levels of the wings and means for regulating the supply of stock to the channels.

In witness whereof we have hereunto set our hands in presence of witnesses.

THEODOR QVILLER. HANS STUB.

Witnesses as to the signature of Theodor Qviller:

THS. BERG, J OH. VAALER.

Witnesses as to the signature of Hans Stub:

SOREN W. MoRoH, J OHN D. BACKMARK. 

